Prevention of loss of produce transported in flats

ABSTRACT

A protective cover for preventing loss of produce from open-topped cardboard flats during transport comprises a flexible sheet of paper coated with a moisture-resistant layer. The sheet has flaps with adhesive strips which may be affixed to sides of the flat after stretching the sheet over the open part of the flat. The protective covers are supplied in stacks, mounted on a rod, and may be torn off one by one. In one embodiment the sheet is supplied in a folded condition in which the moisture-resistant layer also serves as a release layer temporarily covering the adhesive strips. In another embodiment, the adhesive strips on all but one layer in the stack are protected by the moisture-resistant layer of a next sheet in the stack. In a third embodiment, the adhesive strips are protected by peelable release liners.

BACKGROUND OF THE INVENTION

[0001] This invention relates to the field of packaging, and particularly to a novel temporary cover for containers known as “flats,” used in the transportation of produce articles such as blueberries, strawberries, cherry tomatoes and the like.

[0002] Relatively small items of produce, such as berries, cherry tomatoes, etc. are typically sold to the consumer in plastics containers each holding multiple units, usually measured in terms of weight, e.g. ½ pound, 1 pound, etc. The plastics containers may be in the form of baskets having film covers, or blow-molded, transparent containers having hinged lids which snap closed. These containers are transported from a food distribution warehouse to food retailers in flats, which are cardboard boxes having a bottom and four sides.

[0003] The tops of the flats are ordinarily at least partially open. Some flats, for example those used to ship cherry tomatoes, are relatively shallow and entirely open at the top. On the other hand, flats used for shipping blueberries typically have flanges which extend from their end walls and overlie part of the contents. The top opening between the flanges may extend downward into the sidewalls. The openings make it easy for retail store personnel to remove containers from the flats for placement on shelves, and of course also reduce costs by eliminating unnecessary material in the flats. The flanges, on the other hand, enable the flats to be placed one on top of another without causing damage to the contents.

[0004] At the warehouse, flats are typically loaded into large trailers, and may be stacked one on top of another. During transport, the contents of each flat except for the uppermost flat in a stack are held in place by the flat or flats above them. The contents of the uppermost flat, however, are not similarly protected, and it is common for blow molded containers to bounce out of the flats in which they are situated. It is also common for the lids of blow-molded containers to snap open when the containers are jarred or dropped, causing the contents to spill. Damage to, or loss of, the contents of other types of containers can also occur if they bounce out of their flats during transport. Spillage of produce in this manner, during transport from the warehouse to the retailer results in significant monetary losses to the wholesaler.

[0005] A retailer often has occasion to return flats of produce previously ordered, and is customarily given credit for intact flats returned. However, as the trailer generally carries a much lighter load on its way back to the warehouse. Because of the reduced load, the trailer tends to be more susceptible to bouncing during the return trip, and consequently there is an even greater likelihood of loss in the case of returns. If the flat is not returned with all of its contents intact, the retailer typically does not receive credit for the returned goods.

[0006] The wholesaler receives flats from a centrally located produce market in flats on skids. The flats on each skid are covered with stretch wrap, and consequently it is rare that the wholesaler will undergo any loss while receiving the produce. Significant losses, however, occur later in the distribution process.

[0007] After the wholesaler receives the skids, the stretch wrap is cut open and the skids are sent to distribution shelves at different locations in the warehouse. At the warehouse, a forklift driver loads various orders into a tractor trailer, on skids. Usually, one or more skids are designated for a specific retail store. A single skid will not ordinarily have two different locations assigned to it. Thus, a partially loaded skid may be sent to a particular retail store. Typically, items less susceptible to damage are placed on the skid first. More fragile items such as berries, cherry tomatoes, etc. are placed on top of other items.

[0008] The flats containing berries, cherry tomatoes, etc. are open at the top. In the peak season there can be as many as five or six layers of berry containers in one flat. Therefore, when the berries, etc. are being transported to the retailer, spillage can occur. The containers in the flats tend to pop open when the flats are jarred during transport. When this occurs, the berries bounce out of the containers. The flats may also slip off their stacks and fall, again causing containers to pop open.

[0009] During the peak season, a single flat of strawberries might cost the wholesaler $17.50, and might be sold to a retailer for $24.00. If some of the berries on the flat are damaged on the way to the retailer, the flat may be sent back to the wholesaler. The wholesaler would then throw out the entire flat and take a loss of at least $17.50. In the off season a similar flat of strawberries might cost the wholesaler $40.00 to $45.00, and might be sold to the retailer for about $53.00. Thus, damage even to a part of the contents of a flat will result in a loss to the wholesaler which, on the average is well in excess of $17.50. In a given year, a single, warehouse of medium size may undergo a loss in the vicinity of $250,000.00 resulting solely to the rejection of flats due to spillage in transport.

[0010] The retailer may also undergo losses due to spillage in transport. For example, a retailer might orders 28 flats of strawberries and actually need only 22 flats. In this situation, referred to in the trade as a “mispick,” the retailer will send the excess flats back to the wholesaler. These flats, riding on the floor of a partially empty tractor-trailer on its way back to the warehouse, sometimes with intermediate delivery stops, are particularly susceptible to damage. They are often completely destroyed by the time they reach the warehouse. The destroyed flats cannot be used, and are thrown out. The retailer bears the cost of loss due to mispicks.

[0011] In practice, if six flats are returned, there is a high likelihood that all six flats will be thrown out. If the retailer was charged $32.50 per flat, for example, the retailer's loss would amount to $195.00.

SUMMARY OF THE INVENTION

[0012] It can readily be seen that the losses to wholesalers and retailers due to spillage of small produce items amount to millions of dollars per year nationwide. An important object of this invention, therefore, is to reduce losses due to spillage of packaged produce. An object of the invention is also to provide a simple, inexpensive, and easily used temporary flat cover to prevent spillage.

[0013] The protective cover in accordance with the invention is designed for preventing loss of produce during transport, where plural packages, each containing multiple units of produce, are contained in a cardboard flat having a bottom and four sides and having an at least partially open top. The protective cover comprises a flexible sheet capable of being disposed in a plane. When so disposed, the flexible sheet comprises a central section having two ends and substantially parallel side edges each extending from one of the two ends to the other. The spacing of the side edges from each other defines the width of the central section. The sheet also comprises a pair of flaps extending in opposite directions from the ends of the central section when the sheet is disposed in a plane. The flaps are preferably narrower than the central section.

[0014] The flexible sheet is composed of a layer of paper having first and second opposite faces. The paper layer may have a moisture-resistant coating on the first face covering at least a major part of the area of the central section, and strips of self-sticking adhesive also on the first face, the strips of adhesive being disposed on the flaps. The protective cover can be affixed to a flat by positioning its central section over the at least partially open top of a flat, with the moisture-resistant coating facing the contents of the flat, and securing the flaps to two of the four sides of the flat by means of the self-sticking adhesive strips.

[0015] Preferably, the sheet is substantially symmetrical about an imaginary line, parallel to, and located midway between, said parallel side edges of the central section.

[0016] The sheet also preferably comprises a pair of tapered sections, each connecting one of the flaps to the central section while minimizing the risk of tearing when the flaps are grasped and pulled away from each other, either to unfold the sheet or to stretch the sheet before securing it to a produce flat.

[0017] The moisture-resistant coating may cover substantially the entire area of the first face of the layer of paper, with the strips of adhesive overlying parts of the moisture-resistant coating. Alternatively, the moisture-resistant coating may cover substantially the entire area of the first face of the layer of paper except for those areas covered by the adhesive.

[0018] In a first major embodiment of the invention, the sheet is folded on itself, along a first pair of parallel creases in the central section thereof, in directions such that the second face is inside each fold at the creases. The sheet is also folded on itself along a second pair of parallel creases such that the first face is inside each fold at the creases of the second pair. The creases are positioned so that the adhesive strips on the first face are directly opposed to, and in contact with, the moisture-resistant coating on the first face, and preferably so that the flaps extend beyond the creases of the first pair. The moisture-resistant coating serves as a release layer allowing the protective cover to be unfolded and brought to a stretched condition by manually pulling on the flaps.

[0019] The protective may be supplied as one protective cover in a stack of substantially identical protective covers, each having a punched hole adjacent to one of its side edges, and the punched holes of all of the protective covers in the stack being aligned with one another.

[0020] In a second major embodiment, the protective cover has a release layer on its second face, the release layer being in two sections, one opposite each adhesive strip. When the protective covers of the second major embodiment are supplied in a stack of substantially identical protective covers, each adhesive strip on all but one of protective covers is in contact with a release layer section on an adjacent protective cover. The protective covers can then be supplied in an unfolded condition. In this case, each protective cover preferably has a punched hole in one of its flaps adjacent to an edge thereof, and the punched holes of all of the protective covers in the stack are aligned with one another.

[0021] When secured to a produce flat having a bottom, four sides, an at least partially open top, and plural packages, each containing multiple units of produce, contained therein and exposed through the at least partially open top, the protective cover has its central section overlying at least part of the exposed packages and preferably at least part of each of the exposed packages. Its flaps are secured to two opposed sides of the four sides of the flat.

[0022] The invention also resides in a novel method for preventing loss of produce during transport, wherein plural packages, each containing multiple units of produce, are contained in a cardboard flat having a bottom and four sides and having an at least partially open top, the method comprising: removing a single flexible sheet from a stack of flexible sheets, each having a central section and a pair of flaps extending laterally from the central section, and exposing a self-sticking adhesive strip on each flap; stretching the removed flexible sheet over the at least partially open top of the flat; and securing the flaps to two opposed sides of the four sides of the flat by means of the self-sticking adhesive strips.

[0023] The self-sticking adhesive strip on each flap of said single flexible sheet is initially protected by a release layer area on a next adjacent flexible sheet in the stack, and exposed by removing the single flexible sheet from the stack.

[0024] Alternatively, the single flexible sheet may be folded when in the stack, and the self-sticking adhesive strip on each flap of said single flexible sheet may be initially protected by virtue of contact with a moisture-resistant release layer formed on said single, flexible sheet, and exposed by pulling the flaps apart from each other, thereby unfolding the sheet following removal of the single flexible sheet from the stack. In still another alternative, the adhesive strips may be protected by peelable release liners.

[0025] The invention affords the produce distributor several important advantages. First, with the protective cover affixed to each flat being shipped, losses due to spillage of packaged produce are substantially eliminated, with a resultant increase in profit both to at the distribution and retail levels. Second, the protective cover is very inexpensive to produce, so that the saving achieved by the elimination of spillage far exceeds the cost of the protective covers. Third, the labor involved in the use of the protective cover is minimal, and it can be used effectively by warehouse personnel without the need for extensive training.

[0026] Other objects, details and advantages of the invention will be apparent from the following detailed description when read in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027]FIG. 1 is an elevational view of a protective cover in accordance with a first embodiment of the invention, showing the cover in a folded condition, as supplied to the warehouseman;

[0028]FIG. 2 is an elevational view illustrating the process of unfolding the cover of FIG. 1 for placement on a produce flat;

[0029]FIG. 3 is an exploded, perspective view, showing the unfolded protective sheet of FIGS. 1 and 2 about to be secured to a flat;

[0030]FIG. 4 is a perspective view, showing the protective sheet secured to a flat;

[0031]FIG. 5 is a perspective view showing a supply of protective sheets, of the kind illustrated in FIG. 1, attached to a post of a warehouse rack;

[0032]FIG. 6 is an elevational view, partly in section, showing the manner in which the supply of sheets is attached to the post of FIG. 5;

[0033]FIG. 7 is a bottom plan view of a protective cover in accordance with a second embodiment of the invention;

[0034]FIG. 8 is a top plan view of the protective cover of FIG. 7;

[0035]FIG. 9 is a perspective view showing a supply of protective sheets, of the kind illustrated in FIGS. 7 and 8, attached to a post of a warehouse rack;

[0036]FIG. 10 is a rear elevation illustrating a protective cover in accordance with a third embodiment of the invention; and

[0037]FIG. 11 is a perspective view of a supply of protective sheets of the kind illustrated in FIG. 10.

DETAILED DESCRIPTION

[0038] The protective cover 10 in accordance with a first embodiment of the invention, as illustrated in FIG. 1, is supplied in the form of a folded sheet. The sheet has a central section 12 having two substantially parallel, straight line side edges 14 and 16. The central section is folded inwardly on itself at creases 18 and 20, and the substantially parallel side edges continue into the folded portions of the central section, terminating at points 22, 24, 26 and 28, which define the ends of the central section. From these points the sheet is tapered inward, having two tapered sections, one being defined between oblique edges 32 and 34, and the other being defined between oblique edges 36 and 38.

[0039] The sheet is again folded, this time outward on itself, at creases 40 and 42, forming outwardly projecting layers. The oblique edges continue into the outwardly projecting layers, terminating at points 44, 46, 48 and 50. Creases 40 and 42 are located in close proximity to each other at intermediate positions in the tapered sections, approximately at the location of an imaginary line which is perpendicular to side edges 14 and 16 and about which the sheet is preferably substantially symmetrical. Flap 52 is defined between parallel, straight edges 54 and 56 of one of the outwardly projecting layers, these edges extending from points 44 and 46 respectively. Flap 58 is similarly defined between parallel, straight edges 60 and 62, which extend from points 48 and 50 respectively.

[0040] The tapered sections allow the flaps to be narrower than the central section of the sheet without significantly impairing the strength of the sheet. Thus, the tapered sections minimize the risk of inadvertently tearing the sheet when the flaps are grasped and pulled away from each other.

[0041] The sheet is preferably formed from paper having a smooth polyethylene coating on one face, which will be referred to as the “bottom face.” The polyethylene coating, seen at 64 in FIG. 1, preferably covers the entire bottom face of the sheet, and serves as a moisture-resistant barrier, preventing moisture from protected produce from weakening the paper layer.

[0042] The sheet also has a pair of self-sticking adhesive strips 66 and 68 (see also FIG. 3) disposed on the flaps. The adhesive material is preferably a double-coated 0.5 mm polyester, permanent adhesive #603XL. The adhesive is available from Converter/Specialties, 245 Route 130, Burlington, N..J. 08016 in the form of a tape, including a layer of adhesive on a release liner. The edges of adhesive strip 66 are indicated at 70 and 72. Adhesive strip 68 has similar edges. The moisture-resistant barrier on the flaps is located between the paper layer and the adhesive strips.

[0043] As will be apparent from FIG. 1, the moisture-resistant polyethylene layer on the inwardly folded parts of the central section is in face-to-face relationship with the adhesive strips, serving as a release layer, to which the adhesive strips adhere weakly. As shown in FIG. 1, the outer ends of the flaps are preferably unglued and project beyond creases 18 and 20, so that they can be grasped and pulled outward. The release layer allows the sheet to be unfolded, in the manner depicted in FIG. 2, by pulling on the flaps.

[0044] A hole 74 is punched in the central section of the sheet near edge 16. This hole is used for hanging the sheet along with others in a stack from which individual sheets can be readily removed. As shown in FIG. 1, the tapering of the tapered sections ensures that hole 74 is exposed when the sheet is folded, in the manner depicted in FIG. 1, with creases 40 and 42 in close proximity to each other. The manner in which a stack of sheets is hung will be described with reference to FIGS. 5 and 6.

[0045]FIG. 3 shows sheet 10 in its unfolded condition above a flat 75, to which it is about to be attached. The flat is a cardboard box having a bottom (not shown), four sides, two of which (end wall 76 and side wall 78) are visible in FIG. 3, and a top which is partly open. Flanges 80 and 82, extend inwardly toward each other from the end walls, providing reinforcement allowing similar flats to be stacked one on top of another, for storage and transport. Tabs 84 project upward from the end walls, and slots 86 are provided at the lower parts of the end walls. The tabs of one flat extend into the slots of a next flat in a stack in order to prevent relative sliding movement of the flats in a stack.

[0046] As mentioned previously, the top of a flat is ordinarily open except between the flanges 80 and 82. Moreover, top opening may extend partially into the side walls in order to save material and to provide easier access to the contents of the flat. For example, wall 78 has a large notch 88 which serves as an extension of the top opening.

[0047] The contents of the flat shown in FIG. 3 consist of plural individual plastics containers 90, containing produce, for example, blueberries, cherry tomatoes, or the like. These containers may be arranged in the flat in one or more layers.

[0048] As shown in FIG. 4, the protective sheet 10 is stretched over the top opening of the flat 75, with its coated bottom facing the interior of the flat, and with the side edges 14 and 16 of its central section parallel to the end walls, of the flat. The flaps extend downward over the outer faces of the side walls and are secured to the side walls of the flat by the self-sticking adhesive strips. Thus, as seen in FIG. 4, the flap 58 of protective sheet 10 is secured to side wall 78 of the flat 75. The central part of the protective sheet preferably, but not necessarily, fits into the notch 88 and the corresponding notch in the opposite side wall so that it firmly engages the containers in the flat. The central part of the protective sheet should be sufficiently wide to engage at least partially all of the containers in the upper layer of containers within the flat.

[0049] In a preferred embodiment of the protective cover, the central section is approximately 33 cm. long (measured in the longitudinal direction, i.e. the direction of elongation of the cover when stretched flat) and 27 cm wide. The rectangular parts of the flaps measure approximately 12 cm in the longitudinal direction and 19 cm. in width. The tapered sections measure approximately 8 cm. in the longitudinal direction of cover. The adhesive strips are about 5 cm wide and are spaced from the ends of the flaps by about 5 cm.

[0050] In another, smaller, embodiment, the central section is approximately 27 cm. long (measured in the longitudinal direction, i.e. the direction of elongation of the cover when stretched flat) and 19 cm wide. The rectangular parts of the flaps measure approximately 7.5 cm in the longitudinal direction and are about 19 cm. in width The tapered sections measure approximately 2.5 cm. in the longitudinal direction of cover. The adhesive strips are about 3 cm wide and are spaced from the ends of the flaps by about 3 cm.

[0051] Protective covers in these two sizes are capable of accommodating most of the produce flats presently in use.

[0052] Flats being transported by truck or trailer, are generally stacked one on top of another on a skid. Flats containing berries, cherry tomatoes and other small items are usually stacked on top of other items on a flat. At least the uppermost flat on each skid has a protective cover affixed to it. Thus, if an uppermost flat in a stack is dislodged, for example by inertia when the vehicle travels over a bump in the road, its protective cover will maintain its contents intact, even if it falls through a considerable distance and even if it is overturned. If an uppermost flat falls off a stack, it exposes the next flat as the uppermost flat, which may also have a protective cover on it. The protective cover on each exposed uppermost flat protects its contents.

[0053] In the warehouse, the protective covers in their folded condition as shown in FIG. 1, are preferably supplied in stacks hung on rods projecting from storage racks. As shown in FIGS. 5 and 6, a storage rack post 90, which is a component of a typical warehouse storage rack, is provided with a vertically aligned series of holes 92 on one side and a series of corresponding holes on the opposite side (not shown). A bolt 94 is located in a selected pair of corresponding holes, as shown in FIG. 6, and secured in place with a nut 96, using washers 98. The length of the bolt should be such that a substantial part of the length of the bolt projects from the post 90, serving as a mounting rod for the stack of protective sheets. A wing nut 100, threaded onto the projecting end 102 of the bolt, holds a stack 104 of folded protective sheets 10 on the bolt, the bolt extending through punched holes 74 in the sheet.

[0054] In the process of preparing a flat for shipment, the warehouseman grasps the frontmost protective cover on the hanging stack of FIGS. 5 and 6, and pulls it to separate it from the stack, tearing the hole 74 in the process. He then pulls the flaps, as shown in FIG. 2, to unfold the protective cover, and places it on the flat in the manner shown in FIG. 4.

[0055] In the alternative embodiment illustrated in FIGS. 7, 8 and 9, the protective sheet 106 is supplied in flat, unfolded condition. The coated bottom face of the sheet can be identical to the coated bottom face of sheet 10 (FIG. 1). Thus, the entire bottom face of sheet 106 is coated, and self-sticking adhesive strips 108 and 110 are provided over the coating on flaps 112 and 114.

[0056] On the top face, separate release layers 116 and 118 are provided on the flaps. These release layers are made slightly wider than the adhesive strips so that, when the protective sheets 106 are provided in a stack 120 as depicted in FIG. 9, the adhesive strips of each sheet are engaged with release layers on the next adjacent sheet. The weak adhesion of the adhesive strips with the release layers keeps the stack intact so that it can be hung easily on a warehouse rack post 122, but allows the individual sheets to be removed easily from the stack for use. In the case of sheets provided in an unfolded condition, the punched mounting holes 124 are preferably provided adjacent to the center of an end edge of a flap, so that the stack of sheets will hang in a vertically elongated condition. A frontmost protective cover is removed from the hanging stack by pulling on its lower flap, tearing the hole 124 in the upper flap. The protective cover is then affixed to a flat in the manner shown in FIG. 4.

[0057] In the embodiment depicted in FIGS. 7, 8 and 9, all of the protective covers in the stack are substantially identical to one another. To facilitate handling of the stack, it is desirable not to expose adhesive on an end sheet in the stack, e.g., the rearmost sheet in FIG. 9. To avoid exposure of the adhesive, an additional sheet (not shown) having a release layer, but no adhesive strips, may be positioned against the end sheet and in contact with the adhesive strips thereon which would otherwise be exposed. Alternatively, the additional sheet may be a front sheet if the adhesive strips face forward. Of course, in instances where exposure of adhesive is not a problem, the additional sheet is not needed. In either case, in the preferred version of the embodiment of FIGS. 7, 8 and 9 an additional sheet may or may not be present. In other words, in the stack, each adhesive strip on all but one of protective covers is in contact with a release layer section on an adjacent protective cover.

[0058] In the embodiment illustrated in FIGS. 10 and 11, the protective cover 126 is primarily parchment, preferably the parchment known as 39 Lb. Original Plain Parchment, approved by the U.S. Food and Drug Administration. Here as in the embodiments described previously, the protective cover has flaps 128 and 130, the rectangular parts of which are narrower than the central section 132, and connected to the central section by tapered sections. The upper flap 128 is longer than its lower flap 130 in the longitudinal direction of the cover, and includes a perforation line 134 parallel to, and spaced about 2.5 cm from, the upper edge 136. A punched hole 138 is provided within the area between the perforation line 134 and upper edge 136. Both flaps have strips of self-sticking adhesive covered by peelable release liners. As shown in FIG. 10, adhesive strip 140 on lower flap 130 is protected by a release liner 142, shown partially peeled away. A similar adhesive strip (not shown) on flap 128 is protected by peelable release liner 144. In a larger version of the protective cover, in which the width of the central section is 27 cm. wide, the adhesive strip is preferably about 2.5 cm. wide, while the release liner is about 7.5 cm. wide. In the smaller version, in which the width of the central section is 19 cm., the adhesive strip is preferably about 2 cm. wide, while the release liner is about 5 cm. wide. In both cases, the excess width of the release liner facilitates removal of the release liner by a warehouse worker wearing gloves.

[0059] The protective covers in accordance with FIG. 10 are preferably supplied in a stack as shown in FIG. 11. The sheets in the stack are held together by a layer 146 of glue which contacts the upper edges of the upper flaps of the sheets. Optionally, the glue layer 146 may be reinforced by a layer of fabric (not shown). The glue layer holds the sheets of the stack together, maintaining the punched mounting holes in alignment with one another, eliminating the need for bands, shrink wrap, or other packaging.

[0060] In use, the stack of protective covers is mounted on a threaded pin 148 extending laterally from a rack element 150, and held in place by a wing nut 152. When an individual cover is needed, the warehouseman pulls the frontmost cover in the stack, tearing it off at perforation line 134. He than peels the release liners 142 and 144 away, exposing the adhesive strips, and places the protective cover on a flat in the manner depicted in FIG. 4.

[0061] All of the above versions of the protective cover eliminate, or at least substantially reduce, losses due to spillage of packaged produce, and increase profit at both the distribution and retail levels. The covers are inexpensive to produce, and the saving achieved by the elimination of spillage far exceeds the cost of the protective covers. Moreover, they are easy to use, and their implementation does not require extensive training.

[0062] Although the protective covers are intended primarily for use in the warehouse in preparing flats for shipment. A supply of protective covers may be kept on hand by the retailer for the purpose of protecting goods being returned, and thereby avoiding losses in return shipments, which as mentioned previously, are borne by the retailer.

[0063] The protective covers of the invention may be modified in several respects. For example, their shapes and dimensions may be changed, and various alternative moisture-resistant layers and self-sticking adhesives may be used. In the embodiment of FIGS. 1-6, the adhesive strips can overlie the moisture-resistant layer, or alternatively, the adhesive strips may be situated in gaps in the moisture-resistant layer and in direct contact with the paper layer.

[0064] Still other modifications may be made to the apparatus and method described above without departing from the scope of the invention as defined in the following claims. 

I claim:
 1. A protective cover for preventing loss of produce during transport, wherein plural packages, each containing multiple units of produce, are contained in a cardboard flat having a bottom and four sides and having an at least partially open top, the cover comprising: a flexible sheet capable of being disposed in a plane, and, when disposed in said plane, comprising a central section having two ends and a pair of flaps extending in opposite directions from the ends of the central section; the flexible sheet comprising a layer of paper having first and second opposite faces, and having strips of self-sticking adhesive on the first face, the strips of adhesive being disposed on the flaps; whereby the protective cover can be affixed to a flat by positioning its central section over the at least partially open top of a flat, with the moisture-resistant coating facing the contents of the flat, and securing the flaps to two of the four sides of the flat by means of the self-sticking adhesive strips.
 2. A protective cover according to claim 1, in which the central section has substantially parallel side edges each extending from one of said two ends to the other, the spacing of the side edges from each other defining a width of the central section.
 3. A protective cover according to claim 1, in which the central section has substantially parallel side edges each extending from one of said two ends to the other, the spacing of the side edges from each other defining a width of the central section, and in which the flaps are narrower than the central section.
 4. A protective cover according to claim 1, in which the paper layer has a moisture-resistant coating on the first face.
 5. A protective cover according to claim 1, in which the central section has substantially parallel side edges each extending from one of said two ends to the other, the spacing of the side edges from each other defining a width of the central section, and in which the flaps are narrower than the central section, and in which said sheet is substantially symmetrical about an imaginary line, parallel to, and located midway between, said parallel side edges of the central section.
 6. A protective cover according to claim 1, in which the central section has substantially parallel side edges each extending from one of said two ends to the other, the spacing of the side edges from each other defining a width of the central section, in which the flaps are narrower than the central section, and in which the sheet also comprises a pair of tapered sections, each said tapered section connecting one of said flaps to the central section.
 7. A protective cover according to claim 1, in which the paper layer has a moisture-resistant coating on the first face, in which said moisture-resistant coating covers substantially the entire area of the first face of the layer of paper, and in which the strips of adhesive overlie parts of the moisture-resistant coating.
 8. A protective cover according to claim 1, in which the paper layer has a moisture-resistant coating on the first face, and in which said moisture-resistant coating covers substantially the entire area of the first face of the layer of paper except for those areas covered by the moisture-resistant coating.
 9. A protective cover according to claim 1, in which the paper layer has a moisture-resistant coating on the first face, and in which said sheet is folded on itself, along a first pair of parallel creases in the central section thereof, in directions such that the second face is inside each fold at said creases of the first pair, and in which said sheet is also folded on itself along a second pair of parallel creases such that the first face is inside each fold at said creases of the second pair, the creases being positioned so that the adhesive strips on said first face are directly opposed to, and in contact with, the moisture-resistant coating on the first face, whereby the moisture-resistant coating serves as a release layer allowing the protective cover to be unfolded and brought to a stretched condition by manually pulling on said flaps.
 10. A protective cover according to claim 9, in a stack of protective covers, in which all of the protective covers in the stack are substantially identical to one another.
 11. A protective cover according to claim 9, in a stack of protective covers, in which all of the protective covers in the stack are substantially identical to one another, each protective cover having a punched hole adjacent to one of its side edges, and the punched holes of all of the protective covers in the stack being aligned with one another.
 12. A protective cover according to claim 1, in which the paper layer has a moisture-resistant coating on the first face, in which said sheet is folded on itself, along a first pair of parallel creases in the central section thereof, in directions such that the second face is inside each fold at said creases of the first pair, and in which said sheet is also folded on itself along a second pair of parallel creases such that the first face is inside each fold at said creases of the second pair, the creases being positioned so that the adhesive strips on said first face are directly opposed to, and in contact with, the moisture-resistant coating on the first face and so that the flaps extend beyond the creases of the first pair, whereby the moisture-resistant coating serves as a release layer allowing the protective cover to be unfolded and brought to a stretched condition by manually pulling on said flaps.
 13. A protective cover according to claim 12, in a stack of protective covers, in which all of the protective covers in the stack are substantially identical to one another.
 14. A protective cover according to claim 12, in a stack of protective covers, in which all of the protective covers in the stack are substantially identical to one another, each protective cover having a punched hole adjacent to one of its side edges, and the punched holes of all of the protective covers in the stack being aligned with one another.
 15. A protective cover according to claim 1, having a release layer on the second face, the release layer being in two sections, one opposite each adhesive strip.
 16. A protective cover according to claim 15, in a stack of protective covers, in which all of the protective covers in the stack are substantially identical to one another, and in which each adhesive strip on all but one of protective covers is in contact with a release layer section on an adjacent protective cover.
 17. A protective cover according to claim 16, each protective cover having a punched hole in one of its flaps adjacent to an edge thereof, and the punched holes of all of the protective covers in the stack being aligned with one another.
 18. A protective cover according to claim 1 in combination with a produce flat having a bottom, four sides, an at least partially open top, and plural packages, each containing multiple units of produce, contained in said flat and exposed through said at least partially open top, the protective cover having its central section overlying at least part of said exposed packages, and having its flaps secured to two opposed sides of said four sides of the flat.
 19. A protective cover according to claim 1 in combination with a produce flat having a bottom, four sides, an at least partially open top, and plural packages, each containing multiple units of produce, contained in said flat and exposed through said at least partially open top, the protective cover having its central section overlying at least part of each of said exposed packages, and having its flaps secured to two opposed sides of said four sides of the flat.
 20. A protective cover according to claim 1, in a stack of protective covers, in which all of the protective covers in the stack are substantially identical to one another, a flap of each protective cover in the stack has a perforation line extending parallel, and in spaced relation, to an edge thereof remote from the central section, the portion of each flap between the perforation line and said remote edge thereof having a punched mounting hole, the mounting holes of all of the protective covers in the stack being aligned with one another, and the said remote edges of the flaps being secured together by a layer of glue, whereby the protective covers of the stack form a tablet from which an individual protective cover can be removed by tearing along its perforation line.
 21. A protective cover according to claim 1, in which each strip of self-sticking adhesive is covered by a peelable release liner having a width substantially greater than the width of the release liner which it covers, whereby the release liner can be grasped easily for removal.
 22. A method for preventing loss of produce during transport, wherein plural packages, each containing multiple units of produce, are contained in a cardboard flat having a bottom and four sides and having an at least partially open top, the method comprising: removing a single flexible sheet from a stack of flexible sheets, each having a central section and a pair of flaps extending laterally from the central section, and exposing a self-sticking adhesive strip on each flap; stretching said removed flexible sheet over the at least partially open top of the flat; and securing the flaps to two opposed sides of said four sides of the flat by means of said self-sticking adhesive strips.
 23. The method of claim 22, in which the self-sticking adhesive strip on each flap of said single flexible sheet is initially protected by a release layer area on a next adjacent flexible sheet in the stack, and exposed by removing the single flexible sheet from the stack.
 24. The method of claim 22, in which the single flexible sheet is folded when in the stack, and the self-sticking adhesive strip on each flap of said single flexible sheet is initially protected by virtue of contact with a moisture-resistant release layer formed on said single, flexible sheet, and is exposed by pulling the flaps apart from each other, thereby unfolding the sheet following removal of the single flexible sheet from the stack. 